The flow of Syrians, Afghans and others through the Balkans toward Western Europe continued unabated as European leaders gather in Brussels to try and work out a plan to deal with the massive influx of asylum seekers.

The flow of Syrians, Afghans and others through the Balkans toward Western Europe continued unabated as European leaders gather in Brussels to try and work out a plan to deal with the massive influx of asylum seekers.

At the Brezice camp in Slovenia near the border with Croatia, a spokesman for the UN refugee agency urged leaders to come up with a system to register and screen newcomers when they first enter Europe, rather than piecemeal along the way .

"But also very important is to help Syria's neighbouring countries where there are around four million refugees," said UNHCR spokesman Babar Baloch. "These people don't need to take these risky journeys if there are legal pathways to come to Europe."

The leaders of EU members Austria, Bulgaria, Croatia, Germany, Greece, Hungary, Romania and Slovenia have been invited to the Brussels summit along with two non-members, Macedonia and Serbia.

A draft plan that they were to discuss has already drawn criticism for its proposal that countries stop allowing asylum seekers to pass across their borders without consulting with their neighbours. Croatian prime minister Zoran Milanovic said that such consultation "is impossible".

Serbian PM Aleksandar Vucic said as he set off for Brussels that he was prepared for "hard, not very pleasant" talks, but hoped leaders could work out a "comprehensive solution".

He said Serbia would not "put up any walls" but suggested his country will not agree to be the only migrant stop if countries farther west close their borders.

Nearly 250,000 migrants have passed through the Balkans since mid-September and the surge is not expected to stop despite colder weather.

Mahmoud Awad, a UNHCR field protection officer working in Serbia, said about 1,000 people passed through the border town of Berkasovo and into Croatia overnight.

Mr Awad said many buses were on hand to help transport people and that everything has been "smooth and calm".

Meantime, Croatian Interior Ministry spokesman Domagoj Dzigulovic said 11,500 people crossed into the country on Saturday, the highest in a single day since asylum seekers started coming to Croatia in mid-September.

Migrants turned to Croatia after Hungary erected a barbed-wire fence along its border with Serbia.

They now mainly travel from Turkey to Greece and then go north to Macedonia and Serbia before entering Croatia and move on to Slovenia and Austria. Most are aiming to get to Germany or Scandinavia.